It is counted as belonging to the state of the art with centrifugal pump assemblies, to lead the delivery flow of the pump along the motor, in order to dissipate the heat produced by the drive motor, so that this motor does not overheat. Such arrangements in particular are known with centrifugal pump assemblies for delivering cold water.
The application of such centrifugal pumps in water supply systems or pressure boosting installations is counted as belonging to the state of the art. With a water supply system which is marketed by the Applicant under the description “GRUNDFOS MQ”, a multi-stage centrifugal pump is arranged in a lying manner, i.e. with a horizontal axis, and which designed in a multi-stage manner and comprises a channel routing within the water supply system, with which water delivered by the pump is delivered from the last pump stage into an annular space which surrounds the electric motor and onto which a channel in turn connects, said channel leading to the exit connection or delivery connection of the water supply system. The design measures which are implemented there for cooling the motor have definitely proven their worth, since the main delivery flow flows along the outer side of the electric motor and thus continuously ensures an adequate cooling. The design of this known water supply system is comparatively complicated, which is why one strives to simplify this, so that the water supply system can be manufactured more economically and can be designed in a technologically more advantageous manner with regard to application. If however, one desires to fundamentally depart from the known design principle, then this also entails a change of the cooling concept for the electric motor.